In the 1950s, a roadworks crew near Canowindra found something remarkable, when blasting unearthed a slab of rock covered in a strange pattern. The slab was saved, and ended up on display at the Australian Museum - along with the complete remains of 114 fossilised fish preserved in the rock.

Since then palaeontologists have learned that the site, 11km west of the central western NSW town, saw a massive fish kill 360 million years ago in the Devonian period.

Today that first slab, along with other fossil records from the site, is housed in the specially built Age of Fishes Museum in Canowindra. One of the museum's volunteers is Greg Morton, whose work at the facility has given him plenty of opportunity to inspect the fossils on display.

"There are a lot of different shells of fish," he explains. "A lot of these species were very heavily armoured, in modern terms they would be like a turtle with a shell. That was their defence mechanism.

"In some cases you can see the actual backbone, the gills, and the dermal layer of the fish."

The imprint of one such backbone stretches almost a metre across two adjacent slabs, while a plaster cast of the head reveals a mouth lined with long, pointed teeth.

"They could look after themselves," Greg observes. "A lot of them had very sharp teeth. The biggest specimen we've found here is about three, maybe three and a half metres long."

Greg says one of the most significant species preserved in the collection is the Canowindra grossi, a creature with both lungs and gills which means it could breath both above and below the water. The one preserved on a slab in the museum is the only known specimen of the species.

From the initial discovery in 1955, it wasn't until 1993 that the site was fully investigated and creatures like the Canowindra grossi came to light. The Australian Museum's palaeontologist Alex Ritchie still has an ongoing relationship with the museum.

"We organise digs away, groups go out to another site we have to see what they can find," Greg says. "We have Dr Ritchie there to oversee it, and anything significant they find is usually added to our collection. Sometimes they go away with a souvenir of their own."